The present invention relates to a power generator and more specifically to an onboard power generator for supplying power to a hoist conveyance, such as a mine shaft elevator or an above-ground elevator.
The mine shaft is the lifeline to underground mining operations. Although there are relatively few injuries and fatalities related to shaft accidents, almost any accident involving hoisting equipment, and in particular a hoist conveyance, has the potential to be catastrophic and injure or kill numerous miners. Between 1992 and 1996, there were approximately 1200 reported accidents involving mine shaft operations. Analysis of these accidents shows that hoisting hazards are often related to falling material, shaft guide misalignment and faulty safety devices. In fact, over 300 of the cited accidents were related to shaft guide misalignment caused by ground instability.
To reduce the potential for hoisting related accidents, sensors and other devices are used to monitor conveyance operating parameters (e.g., rope tension, conveyance load and conveyance position). Feedback from the monitoring devices can then be used to address potential problems before a catastrophic accident occurs. Mounting such devices onboard the conveyance itself, such as to the top of the conveyance cage, is desirable in that accurate, real time measurements relating to the operation of the conveyance can be obtained.
When mounting various monitoring devices onboard a conveyance, a reliable source of electrical power is required. It is known that hoist conveyances employ a traveling cable connected between the conveyance and the control room to provide electrical power to the conveyance. In relatively deep mine shafts (e.g., greater than 600 feet deep), however, it is not feasible to employ a traveling cable. In such deep shafts, information must be via radio or other remote means having its own on-board power source. Thus, well-charged batteries onboard the conveyance are a necessity.
The present invention is directed toward an onboard power generation apparatus for a hoist conveyance, such as a mine shaft elevator or an above-ground elevator. In one embodiment of the invention, a drive wheel is carried by the conveyance. The drive wheel is positioned to engage the surface of a stationary structure adjacent the conveyance, such as a shaft guide, so that vertical movement of the conveyance relative to the structure causes rotation of the drive wheel. The drive wheel may include an elastomeric outer tread layer to minimize slip between the drive wheel and the surface of the adjacent structure. A charging generator, which is coupled to the drive wheel, is operable to produce an electric current upon rotation of the drive wheel to provide power to the conveyance.
A battery may be electrically connected to the generator so that the generator provides an electric current to recharge the battery upon movement of the conveyance. The battery may be used to power a voice communication system or any of various onboard conveyance monitoring devices, such as an encoder for determining the vertical position of the conveyance or a potentiometer for determining lateral displacement of the shaft guides or a load cell to determine wire rope tension or an accelerometer (e.g., a two-axis accelerometer) for determining the acceleration of the conveyance.
The apparatus also may include biasing mechanism for resiliently biasing the drive wheel toward the surface of the adjacent structure. In one disclosed embodiment, the drive wheel and the charging generator are mounted on a common support. The support is mounted for movement relative to the conveyance in a direction generally perpendicular to the central axis of the drive wheel and toward the surface of the adjacent structure. At least one spring is operatively connected to the support and to the conveyance to bias the support toward the adjacent structure to maintain contact between the drive wheel and the surface of the structure.
According to another embodiment, a power generation apparatus for supplying power to a vertically movable hoist conveyance comprises a generator carried by the conveyance. The generator includes at least one drive wheel rotatably coupled thereto and operable to contact the surface of an adjacent stationary structure so that movement of the conveyance causes rotation of the drive wheel to generate an electric current. The drive wheel is mounted on a support that is operable to move with respect to the conveyance to accommodate variations in the surface of the adjacent structure as the conveyance moves vertically relative to the structure.
In another embodiment, power generation apparatus is mounted onboard a mine hoist conveyance having guide wheels for engaging shaft guides and onboard instrumentation for monitoring the operation of the conveyance. The apparatus includes a battery for supplying power to at least the instrumentation of the conveyance. A generator is carried by the conveyance and operatively connected to one of the guide wheels of the conveyance to produce an electric current upon movement of the conveyance. The generator is electrically connected to the battery to recharge the battery.
Finally, a method for generating power for a hoist conveyance operable to move vertically through a shaft comprises providing a generator assembly for mounting on the conveyance. The generator has at least one wheel for contacting a substantially stationary surface in the shaft. Thus, an electric current is generated when the wheel rotates upon vertical movement of the conveyance. The method may further include recharging a battery onboard the conveyance with the electric current. In addition, the wheel of the generator assembly may be resiliently biased toward the surface in the shaft to accommodate variations in the surface as the conveyance is moved.
The foregoing and other objects, features, and advantages of the invention will become more apparent from the following detailed description of several embodiments, which proceed with reference to the accompanying figures.